Modular structures, meaning structures comprised of identical repeated components, provide significant construction advantages as components can be prefabricated and mass-produced. Modules can also be designed to be used to form many different types of structures (e.g., different depths, spans). They can also be re-used. Modular design and construction can reduce the overall project cost and project schedule. Modular approaches can be used for a wide variety of structures, including bridges and buildings.
Modular bridges are comprised of prefabricated components or panels that can be rapidly assembled on site. Existing modular or panelized steel bridging systems (e.g., Bailey, Acrow, Mabey-Johnson) consist of rigid rectangular steel panels that are connected by pins and are arranged in a longitudinal configuration to form a girder-type bridge. They have also been used in alternative configurations to construct bridge piers, suspension bridges, movable bridges, and buildings, as well as for temporary formwork or scaffolding for construction. These modular bridges were developed to serve needs in rapid construction in war, but have also been widely used in emergencies and disasters. Early attempts at modular bridging included the Callender-Hamilton Bridge which was comprised of individual steel members bolted together on site. These were later replaced by the Bailey Bridge system, and its derivatives, which featured rigid panels connected by pins that were easier and faster to erect.
These prior art systems feature rigid, rectangular modules (typically 10 ft in length, see for example a Bailey panel 10 in FIG. 1A) which are connected longitudinally (by pin connectors 11 in FIG. 1B) to form girder-type bridges. Versatility of these existing systems is achieved by stacking modules vertically and/or transversely to reach longer spans (up to 200 to 300 ft) and/or higher load capacity (see for example the double-triple configuration—meaning two modules stacked transversely and three modules stacked vertically—of a Bailey system 12 in FIG. 1C).
A primary limitation of the existing technology is that a fixed panel size limits the span length. More specifically, the span is limited by buckling. Lateral bracing 13 in FIG. 1C can be utilized between planes of stacked panels to mitigate buckling failures. However, lateral bracing is expensive and time-consuming to install. Geometric challenges also result in a stacked through-type bridge. Further, buckling failures can still occur. Additional limitations include that the pin connection between panels are less reliable than other types of connections between structural members. Also, the structural depth along the span is not varied despite varying moment and shear demand, resulting in an inefficient use of materials. Accordingly, there is a demonstrated need for an improved approach to modular construction as declared herein.